Aircraft configuration with improved aerodynamic performance

Abstract

An aircraft ( 10 ), in particular a trainer aircraft with improved aerodynamic performance, having a configuration able to keep a directional stability and a very good aerodynamic behaviour even at very high angles of attack, where, traditional configurations prove themselves inefficient. In particular, this configuration foresees a forebody ( 52 ) with variable section, optimised for high angle of attack flights, a LEX vortex control device ( 72 ) at least one diverterless air intake ( 46 ), and a wing profile ( 18, 20 ) optimised in order to reduce the buffet effects typical of low aspect ratio wings with thin profile and variable camber. The aircraft ( 10 ) presents, finally, staggered tails ( 44 and 38 ), to optimise the aerodynamic performance.

1. Configuration of an aircraft ( 10 ) with improved aerodynamic performance, so as to maintain direction stability at mid/high angles of attack, said aircraft ( 10 ) having a fuselage ( 12 ) fitted with wings ( 18 ,  20 ) and leading edge extensions each leading edge extension (“LEX”) having an area at least one air intake ( 46 ) and a fuselage forebody ( 52 ) with a tapering section, said aircraft ( 10 ) including a LEX vortex control device ( 72 ) shaped such as to make symmetrical the bursting of the vortex generated by a said LEX at mid/high angles of attack, wherein the ratio of the LEX area over the corresponding LEX vortex control device height is equal to 2.35m with a tolerance range varying from about 200% to about 50% of said ratio, said LEX vortex control device cooperating with staggered tails comprising a single vertical fin ( 38 ) and at least one horizontal stabilizer ( 44 ), obtained by coupling the vertical fin ( 38 ) to the wing ( 18 ,  20 ), wherein the leading edges ( 36 ) of the vertical fin ( 38 ) overlap the tailing edges ( 70 ) of each wing ( 18 ,  20 ), in order to maintain lateral-directional stability. 
   
   
     2. Configuration of an aircraft ( 10 ) as defined in  claim 1 , wherein the fuselage forebody ( 52 ) has a low aspect ratio. 
   
   
     3. Configuration of an aircraft ( 10 ) as defined in  claim 1 , wherein the staggered tails ( 44  and  38 ) are coupled by the vertical fin with trapezoidal platform to the wing ( 18 ,  20 ) and whose leading edges ( 36 ) overlap trailing edges ( 70 ) of each wing ( 18 ,  20 ). 
   
   
     4. Configuration of an aircraft ( 10 ) as defined in  claim 3 , wherein the horizontal stabilizer ( 44 ) comprises a trapezoidal platform and the capability of symmetrical and asymmetrical deflection, said horizontal tail having a hinge axis ( 86 ), along a lateral axis ( 88 ) of the aircraft ( 10 ), in order to optimize hinge and inertial moments. 
   
   
     5. Configuration of an aircraft ( 10 ) as defined in  claim 3 , wherein the air intake ( 46 ) has no diverter on the upper lip of the air intake. 
   
   
     6. Configuration of an aircraft ( 10 ) as defined in  1 , wherein the air intake ( 46 ) has an inner lip average leading edge radius ( 76 A) equal to 7 mm, while the lower lip average leading edge radius ( 78 ) is equal to 17.5 mm and that of the average outer lip ( 80 ) is equal to 14 mm, so that the capture area of the air intake ( 46 ) is about 0.322 m 2 , the throat area is about 0.257 m 2  and the engine face area is about 0.273 m 2 . 
   
   
     7. Configuration of an aircraft ( 10 ) as defined in  claim 1 , wherein each wing ( 18 ,  20 ) of the aircraft ( 10 ) has a trapezoidal platform and at least one saw tooth area (S) in at least one part of the wing span, said wing ( 18 ,  20 ) also having a leading edge ( 68 ) and radius (R) with a triangular profile. 
   
   
     8. Configuration of an aircraft ( 10 ) as defined in  claim 1 , wherein each wing ( 18 ,  20 ) of the aircraft ( 10 ) shows a variable camber profile, both on the leading edge ( 66 ) and on the trailing edge ( 70 ), in order to optimize camber profile for improved compressibility effects. 
   
   
     9. Configuration of an aircraft as defined in  claim 1 , wherein the LEX control device is substantially vertically oriented. 
   
   
     10. Configuration of an aircraft as defined in  claim 1  wherein a LEX control device is located at about the tip of each LEX, where said LEX meets an adjacent wing. 
   
   
     11. Configuration of an aircraft as defined in  claim 1  wherein a LEX control device is substantially vertically oriented at about the tip of said LEX, where said LEX meets an adjacent wing. 
   
   
     12. Configuration of an aircraft as defined in  claim 1  wherein the ratio of the LEX area over the corresponding LEX vortex control device height is equal to about 2.35m.